1. Field
The present disclosure is related to semiconductor elements and an organic light emitting display device having a semiconductor element.
2. Description of the Related Art
A conventional semiconductor element having a bottom gate configuration generally includes a gate electrode disposed on a substrate, a gate insulation layer disposed on the gate electrode, an active layer disposed on the gate insulation layer, an etching stop layer disposed on the active layer, and a source electrode and a drain electrode disposed on the etching stop layer. The source electrode and the drain electrode may contact a source region and a drain region of the active layer.
In the conventional semiconductor element of the bottom gate configuration, the etching stop layer may include a first opening and a second opening. Each of the source and drain electrodes may contact the active layer through the first and second openings. For example, the openings may be formed in the etching stop layer via the dry or wet etching processes. In this case, since electrons are trapped in a contact surface where the source electrode to which a high power supply voltage is applied contacts the active layer, a threshold voltage (Vth) of the semiconductor element may be changed. Accordingly, the semiconductor element may have degraded electrical characteristics such as the increase of the threshold voltage distribution, the decrease of the driving current, etc. Particularly, when the conventional semiconductor element includes an active layer having an oxide semiconductor, the conventional semiconductor element may be relatively sensitive to the change of the electrical characteristics, and thus the conventional semiconductor element may malfunction. Such a degraded semiconductor element may not be properly employed in recent display devices such as liquid crystal display (LCD) devices, organic light emitting display (OLED) devices, etc.